Hydraulic steering gear



Aug. 16, 1949.,

P. E'. FoRsYTHE 2,479,063

l HYDRAULIC STEERING GEAR Filed Feb. 1l, 1946 5 Sheets-Sheet 1 Aug. 16, 1949.

P. E. FORSYTHE HYDRAULIC STEERING GEAR Filed Feb. 11,.r 1946 3 Sheets-Sheet 2 INVENToR. fw f. Fosvr/if' ,V5 d y,

P. E. FoRsYTHE 2,479,063

HYDRAULIC STEERING GEAR 3 Sheets-Sheet 3 Y w y .ww

Aug. 16, 1949.

Filed Feb. ll, 1946 neutral position, the pin 3| coincides with the axis of the rudder post 6.

Making connection with the forward wall port i5 are a pair of fluid-now pipes 44 and 45 connecting, in the one instance, with the rear end of the lower starboard cylinder I3 and, in the other instance, with the forward end of the lower port cylinder 9. Return connections 46 and 41 extend between the other ends of these cylinders and the rear wall port 4I. From the drain opening of the valve chest, a pipe 48 carries to an overhead relay tank 50 Vented as atr5If, and from this tank an overflow pipe 52 leads to a base reservoir 53.

55, and provided as a continuous source of power Drawing oil through 4a pipe 54 from this reservoir is a constant-pressurepump Fig. 1). The pump feeds back through a pipe 51 to the center port 42 of the valve chest, andV introduced in this pipe is a check valve 58 opening with the pressure of the pump. Between the pipe 51 and the-pipe 48 are by-pass connections tted one with a pressure-relief valve 59 and the other with a check valve 6D, the check-valve closing by the pressure obtaining within the pipe 51.

Now in respect of theother cylinders I I and I5, there are provided pipes from opposite ends of each which make connection with the two sides of a hand pump 6I, andarranged and adapted to activate this hand pump through intermeshing gears 62-63 is'the vessels steering wheel 64, the desired placement of the hand pumpvbeing one in which the same is housed in the base part of the wheel stand, and in which this base serves as a reservoir for the oil being pumped by the hand pump. The hand pump is of the reversing type, and which is to Vsay that the two sides exchange induction and eduction significance by the impartation of opposite directions of rotation to the steering wheel. Pipes leading from these two sides of the pump 6I are designated 65 and 56.

`Before proceeding Vto describe the piping between the hand pump and the top cylinders II and I5, it is here stated-and which would follow a wheel mounting in which clockwise direction dictates a right rudder and, conversely, counterclockwise direction a left rudder-thatclockwise directional movement of the steering wheel acts upon the hand pump such that the side connecting with the pipe B5 becomes the leduction side and the side yconnecting with the pipe 66 the induction side. VFrom this pipe 65 connection is made by a pipe 61 with two branch pipes 68 and 69, and one of these branch pipes leads to the forward end of the top port cylinder I I While the other branch pipe connects with the rear end of the top starboard cylinder I5. From the pipe 65 connection is had through a pipe 10 with two branch pipes 1I and 12, and theseV two branches connect with the other ends of the top cylinders. namely the pipe 1l with the rear end of the port cylinder I I and the pipe 12 with the forward end of the starboard `cylinder I5.` For connecting the pump with the reservoir a, nipple 13 threads into a wall opening of the latter and supplies oil to a valve body 14 having therein a double-acting check valve 15, the valve body providing separate connections one to the pipe 65 and the other to the pipe SB with the action of the check valve being such as to automatically isolate the eduction side of the pump from the reservoir while bringing the induction sidev into communication therewith.

Applied to the wheel stand is the usual ruddervfrom through the pipe 48 and the relay tank 55 back to the reservoir 53. Block 25 being stationary by reason of the helmsman holding the Wheel in its amidships position, any drift of the rudder with responsive slight movement of the yoke moves the floating levers fulcrum 28 and the `lever then acts about pin 24 as an axis to move the valve spool to a position which throttles the valves oil flow, creating a pressure sufficient to hold the rudder. VIf the pressure builds up too high the plungers 8 and I2 will bebrought into play to move the rudder ahead, and such rudder movement will move the oating lever to open the valve more. If the pressure is too lowthe rudder will drift back and will close the valve to increase the pressure. Thus, the iioating lever connection serves to set the valve spool to a position that will throttle the pump flow to a pressure equal to that developed byV rudder torque.

Assume now that the helmsman turns the steering wheel to eiectuate a right rudder condition, the eduction fluid flowing through pipe G8 to the rear end of the cylinder I5 forces the pilot piston I4 forwardly and causes pin 24, which moves in unison therewith, to pivot the floating lever about pin 28 as an axis. The spool 35, responding, is made to shift rearwardly to bring the pump line 51 into communication with the rear port 4I while isolating the pump from the front port 40. The pumped oil thus feeds to the front end of the port power cylinder 9 and to the rear end of4 the starboard power cylinder I3 to accomplish right rudder. Rudder movement reverses the movement of the shuttle valve to stop pump ilow. If the hand pump is turned rapidly, the slide block is brought up hard against the yoke and hand energy given to the steering wheel augments the pump 55 to aid in driving the rudder. If the hand pump is made to turn slowly, the rudder will then close the shuttle valve as fast as the hand pump opens the valve, the swinging speed of the rudder consequently being in correspondence with the speed of the helm. The rudder, it will thus be seen, follows the position of the helm within the limits of the lost motion provided between block 25 and yoke arm 25, and I have engineered the system such that this lost motion is equivalent to one degree of rudder on each side of neutral, transmitting to the spool 35 a movement of 0.42 each side of neutral to assure sufcient travel for a positive valve opening, this said engineered travel of 0.42 being the maximum travel of the spool under any condition, each way considered, due to the fact that the pin 3|, in the normal positioning of the floating lever, coincides with the axis of the rudder stock. The power pump which I employ is a Vickers vane type V-104 rated for continuous operation at 1000 p. s. i., and tests conducted show a minimum throttle pressure of approximately 20 p. s. i. with the negative lap on the lands of the spool of 1%". Inasmuchras rudder movement depends onrthe valve movement to obtain the throttling action which will build up sufcient pressure to hold the rudder, and 1%" of valve motion connection; a continuously driven main pump; a reversible-flow manually operable transmitter pump; iiuid-ow connection from one side of the transmitter pump to one end of the pilot motors cylinder and from'the other side of the transmitter pump to the other end of said cylinder; -a shuttle-type control valve providing a valve spool and a four-way valve body for the spool; fluid-flow pipes connecting two of the four ports of the four-way valve body one to `one end and the other to the other lend of the power motors cylinder; vfluid-flow pipes connecting the remaining two ports of the valve body one with the induction side and the other withthe eduction side of the main pump, the arrangement as betweenthe valve spool and said ports being such that pressure fluid is given free passage between eduction and induction sides of the main pump upon a neutral positioning of the spool and serves to connect said eduction side with one end and the induction side with the other end of the power motors cylinder, selectively, by movements of the spool in opposite directions from neutral; a mechanical connection from the pilot motor to the valve spool functional by Isuch activation of the former as takes up the lost motion in said motors connection with the tiller to move the spool from neutral, thus to activate the power motor and drive the tiller, and by a responsive overtake by the tiller of said lost-motion travel of the pilot motor to move the spool back to neutral, said tiller being comprised of a yoke with both the power motor and the pilot motor each having their connection with one end of said yoke, and means to augment said described motorscomprising a second motor made responsive to the pressure of the main pump anda second motor made responsive to the pressure of the transmitter pump, the two motors last named being each direct-connected to the other end of the yoke.

3. In a hydraulic steering system having a power motor and a pilot motor, each pressurefluid actuated and each operatively interconnected with the vessels tiller, the one directly and the other through a lost-motion connection; a continuously driven main pump; a reversibleow manually operable transmitter pump; fluidflow vconnections from respective sides of the transmitter pump to the pilot motor acting by flow of pressure fluid through one to activate the pilot motor for operation in one direction and by flow of pressure fluid through the other to 'V activatel the pilot motor for operation in the other direction; a shuttle-type control valve providing a valve spool and a four-way valve body for the spool; fluid-flow pipes connecting two ,of the four ports of the four-way valve body with the power motor, the delivery of pressure fluidv through one of said pipes activating the power motor for loperation in one direction and the delivery of pressure fluid through the other of said pipes activating the power motor for operation in the other direction; fluid-flow pipes connecting the remaining two ports of the valve body one with the induction side and the other with the eduction side of the main pump, the arrangement as between the valve spool and said ports being such that pressure fluid is given free `passage between eduction and induction sides of the main pump upon a neutral positioning of the spool and serves to connect said eduction side with one and the induction side with the other of said two pipes which connect with the: power motor, selectively, by movements of the spool in opposite directions from neutral; a fluid-now pipe connecting eduction and induction sides of the main pump and fitted with a check valve closing with the pressure of the pump; and a mechanical -connection from the pilot motor to the valve spool functionalV by such activation of the former as takes up the lost motion in vsaid motors connection with the tiller to move the spool from neutral, thus to activate the power motor and drive the tiller, and by a responsive overtake by the tiller of said lost-motion travel of the pilot motor to move the spool back to neutral.

4. In a hydraulic steering system having a power motor and a pilot motor, each pressurefluid actuated and comprised of a double-acting piston and a cylinder therefor and each operatively interconnected with the vessels tiller arm, the one by a positive connection and the other by a lost-motion connection, said positive Connectioncomprising a piston-rod anda wrist pin therefor which is held stationary with respect to the tiller arm, and said lost-motion connection comprising a piston rod and a wrist pin therefor which is given limited slide movement in respect of the tiller arm; a continuously driven main pump; a reversible-flow manually operable transmitter pump; fluid-flow connection from one side of the transmitter pump to one end of the pilot motors cylinder ,and from the other side of the transmitter pump to the other end of the pilot motors cylinder; a shuttle-type control valve providing a valve spool and a four-way valve body for the spool; fluid-flow pipes connecting two of the four ports of vthe four-way valve body one to one end and theother to the other end of the power motors cylinder; fluid-flow pipes connecting the remaining two ports of the valve body one with the induction side and the other with the eduction side ofthe main pump, the construction of said valve spool and its relation to said ports being such that pressure Vfluid is given free passage betweeneduction and induction sides of the main pump upon a neutral positioning of the spoolV and, by movements of the spool in opposite'directions from neutral, serves to connect said eduction side with one end and the induction side with the other end of the power motors cylinder, selectively; `a fluid-now pipe connecting eduction and induction sides of the main pump and fitted with a check valve closing with the pressure of the pump; and a connection from the said slidably mounted wrist pin to the valve spool functional by such activation of the pilot motor as takes up the lost motion between wrist pin and tiller arm to move the spool from neutral, thus to activate the power motor and drive the tiller, and by a responsive overtake by the tiller of said lost-motion travel of the slidably mounted wrist pin to move the spool back to neutral.

5. Structure according toV claim 4 wherein said spool-moving connection comprises a oating lever fulcrumed intermediate its length to the tiller arm and connected by its outer end to the slidably-mounted wrist pin and by its inner end to a link which is in turn connected to the spool, the connection from the inner end to the link comprising a pivot pin disposed to have its axis coincide with the axis of the vessels rudder post upon a positioning of the sliding wrist pin at the mid-point of its sliding movement.V

6. In a hydraulic steering system having a power motor and a pilot motor, each pressureone with the pilot motor and the other with the control valve and each placed to occupy a position angular to the tiller arm, a floating lever fulcrumed to the tiller arm for rocker movement about an axis offset from but parallel to the turning axis of the tiller arm and pivotally connected to said control rods at separated points offset from the fulcrum of the lever, one of said pivotal connections being permitted a. limited slide movement in relation to the tiller arm and the other said pivotal connection being so placed that its axis coincides with the turning axis of the tiller arm upon a positioning of the sliding pivot at .the approximate mid-point of its sliding movement.

12. A hydraulic steering system comprising a power motor and a pilot motor each pressurefluid actuated and each connected with the vessels tiller arm the former said motor by a positive connection and the latter said motor by a lost-motion connection, said positive connection -comprising a piston rod and a wrist pin therefor which is held stationary with respect to the tiller arm and said lost-motion connection lcomprising a piston rod and a wrist pin therefor which is given a limited slide movement in respect of the tiller arm; a continuously driven main pump functionally associated with and made active at will to the pilot motor; and a control valve for the main pump hooked to the pilot motor for direct response to the operations of the latter and characterized in that the same is made instantly effective to bring the main pump into operating couple with the power motor by su-ch an activation of the pilot motor vas takes up said lost motion and to operatively uncouple the main pump from the power motor as the activated tiller arm responsively overtakes said lost motion travel, said hook-up as Ibetween the control valve and the pilot motor comprising control rods ccnnected one with the pilot motor and the other with the control valve and each placed to occupy a position angular to the tiller arm, a oating lever iulcrumed to the tiller arm for rocker movement about an axis offset from but parallel to the turning -axis of the tiller arm and pivotally connected to said control rods Iat separated points offset from the fulcrum of the lever, one of said pivotal connections being permitted a limited slide movement in relation to the tiller arm and the other said pivotal connection being so placed that its axis coincides With the turning axis of the tiller arm upon a positioning of the sliding pivot at the approximate mid-point of its sliding movement.

13. A steering system comprising a power motor pressure-huid actuated and direct-connected to the vessels tiller arm for unitary movement with the latter; a manually governed pilot motor having lost-motion connection with the tiller arm; a continuously driven pump functionally associated with but normally inactive to the power motor; and a control valve for the pump positively hooked to the pilot motor for direct response to the operations of the latter and characterized in that the same is made effective to bring the pump into operating couple with the power motor by such an activation of the pilot Number motor as takes up said lost-motion and to operatively uncouple the pump from the power motor by a responsive overtake from the activated tiller arm of said lost-motion travel, said hook-up as between the control valve and the pilot motor comprising control rods connected one with the pilot motor and the other with the control valve and each placed to occupy a position angular to the tiller arm, a oating lever fulcrumed to the tiller arm for rocker movement about an axis offset from but parallel to the turning axis of the tiller arm and pivotally connected to said control rods `at separated points olset from the fulcrum of the lever, one of said pivotal connections being permitted a limited slide movement in relation to the tiller arm and the other said pivotal connection being so placed that its axis coincides with the turning axis of the tiller arm upon a positioning of the sliding pivot at the approximate mid-point of its sliding movement.

14. A hydraulic steering system -comprising a power motor of a double-acting nature operated by pressure fluid and direct-connected to the vessels tiller arm for unitary movement with the latter; a manually governed pilot motor having lost-motion connection with the tiller arm; a continuously driven and uni-directional main pump; fluid-flow connections normally isolated from the pump and connecting one with one end and .the other with the other end of the power motor; a control valve arranged to selectively bring said huid-flow connections one into communication with the high-pressure side and the other into communication with the low-pressure side ofthe pump; and a system of rigid links hooking the valve to the pilot motor for direct response to the operations of the latter and also having operative interconnection with the tiller arm such that turning movements of the tiller arm modify the action of the linkage and transmit movement to the control valve, said hook-up as between the control valve and the pilot motor comprising control rods connected lone with the pilot motor and the other with the control valve and each placed to occupy a position angular to the tiller arm, a floating lever fulcrumed to the tiller arm for rocker movement about an axis offset from but parallel to the turning axis of the tiller arm and pivotally connected to said control rods at separated points oiset from the iulcrum of the lever, one of said pivotal connections being permitted a limited slide movement in relation to the tiller arm Iand the other said pivotal connection being so placed that its axis coincides with the turning axis of the tiller arm upon a positioning of the sliding pvot at the approximate mid-point of its sliding movement. PAUL E. FORSYTHE.

REFERENCES CITED The following references are o f record in the iile of this patent:

UNITED STATES PATENTS Name Date 1,292,029 Paine Jan. 21, 1919 2,343,689 Mercier July 23, 1942 

